Copying apparatus and control therefor

ABSTRACT

An improved copying apparatus has control means for transporting sheets of copying material from a stack and has an exposure device along which an original can be guided. By actuation of a switch, when an original is inserted, a copy paper is moved, by rollers associated with the stack of copy paper, from a ready position in order to transport the copy paper, synchronously with the original, through the exposure device and through processing devices upstream and downstream of the exposure device. The ready position of the copy paper is determined by a switch in the path of the copy paper, and this switch is actuated by the arrival of the copy paper and stops the withdrawal means. The switch is released after the passage of the copy paper so that one copy paper follows another in succession into the ready position.

United States Patent Inventors Appl. No.

Filed Patented Assignee Priority COPYING APPARATUS AND CONTROL THEREFOR13 Claims, 8 Drawing Figs.

05. CL 355/14 Int. Cl. 603g 15/00 Field of Search 355/]06.

Primary Emminer-Sam uel S. Matthews Assistant Examiner-Russell E. Adams,Jr. Attorney McGlew and Toren ABSTRACT: An improved copying apparatushas control means for transporting sheets of copying material from astack and has an exposure device along which an original can be guided.By actuation of a switch, when an original is inserted, a copy paper ismoved, by rollers associated with the stack of copy paper, from a readyposition in order to transport the copy paper, synchronously with theoriginal, through the exposure device and through processing devicesupstream and downstream of the exposure device. The ready position ofthe copy paper is determined by a switch in the path of the copy paper,and this switch is actuated by the arrival of the copy paper and stopsthe withdrawal means. The switch is released after the passage of thecopy paper so that one copy paper follows another in succession into theready position.

PATENTED JUL 1 319m SHEET 2 OF 6 km g MN m PATENTEDJULHIBII 3592.540

SHEET 3 [1F 6 PATENTEU JUU 3 197! SHEU 5 BF 6 COPYING APPARATUS ANDCONTROL THEREFOR The invention relates, as indicated, to copyingapparatus.

In a known construction, the withdrawing means for the copy paperconsists of a unit, comprising a withdrawing roller resting on the topsheet of a copy paper stack, and a pair of ready position rollersdownstream thereof are held resiliently in contact with each other.Behind this pair of rollers, there is arranged a switch determining theready position. Following, in spaced relationship, is transport devicesrequired in the apparatus, such as pairs of rollers. These rollers arein contact with each other and receive the copy paper after it leavesthe ready position. This unit is controlled by a common drive, such as acommon clutch for all rollers.

This known construction has several drawbacks. A paper in the readyposition is under the pressure of two contacting rollers, in which thecontact pressure must be strong enough to produce a definite transportengagement. This could damage the sensitized coating of the copy paper,if it is held in the ready position for a longer period. In addition,during the entry of the leading edge of the copy paper not yet definedby the withdrawing roller, difficulties may arise because this rollermay operate with a certain amount of slip.

The copy paper feed is started when the leading edge of the originalactivates, via a contact switch, a drive arrangement for the withdrawingand "ready" position rollers. The copy paper continues to move into aposition where is can be gripped by the other rollers of the copy papertransportv In the known apparatus, the copy paper feed unit is stoppedonly after the trailing edge of the copy paper has past by the "ready"position contact switch. During this period, both the feed and transportrollers are in driving engagement with the copy paper. With smalldifferences present in the driving speed of the two sets of rollers, theresulting friction between the rollers and the copy paper may produceundesired effects.

The previous solution to this problem was to have the original activatethe ready position and with driving rollers for a short direction andreduce the spacing between the pairs of ready position and transportrollers. Upon deactivation, the ready position rollers were allowed tofree wheel as the copy paper engaged the transport rollers. Such asolution, however, is incomplete since the rollers are still in contactwith the paper. An added drawback in the known device is the function ofthe ready position switch. The switch will allow a second sheet of copypaper to be fed only after the trailing edge of the first sheet has pastby the switch. This produces a considerable gap between the two sheetswhich results in loss of copy time.

Furthermore, the known arrangement has the drawback of an expensivecontrol, because the unit comprising the withdrawing roller is not onlystopped by the copying paper actuated switch, but also started thereby,and the same process is also carried out in the reverse order by thestop switch actuated by the original.

It is the object of the invention to solve these drawbacks by meanspermitting a simpler control and handling of the copying paper in a morecareful manner, while the withdrawing means is switched off only by thearrival of the copying paper in the ready position.

It is another object of the invention to provide a device of the kindabove described in which the stop or limit switch for the originalswitches the drive for the copying paper by a temporarily effectiveadvancing or feed element (advancing and contact pressure roller), aswell as the separate drive of the withdrawing roller on the stack, whichroller is equipped with a freewheeling device. The feed member forms, inthe inoperative position with a continuously revolving synchronousmember, a gap adapted to receive the copying paper, while being inworking engagement in the operating position until the copying paper hasbeen gripped by other transport mechanisms, with the copying paper beingreleased in the reforming gap. The drive for the withdrawing roller hasa lower speed than that of the feeding element, and the freewheelingdevice is attached to the withdrawing roller in such a way as to allowthe copy paper to be taken up at the speed of the feed elements. Thetransport of the next sheet is begun as soon as the freewheeling deviceengages the drive, thus minimizing the gap between copy paper sheets andreducing time delay between introduction of originals.

Since the withdrawing means comprise only one roller and the otherelements of this unit are missing, the frictional forces acting duringthe withdrawing of the copying paper are substantially smaller,especially in view of the fact that the freewheeling device is mounteddirectly between the shell of the withdrawing roller and its associatedshaft. The careful treatment of the paper is further improved by thecopying paper resting in the ready position in a free space between theready position rollers the paper has been transported to the transportmechanism.

Such an arrangement has already been proposed in German Pat. applicationNo. L 56277 VlIlb/l 5e.

In conjunction with the freewheeling device, this construction has theadvantage that, after transportation by means of rotating thecounterpressure roller equipped with the flat, the copying paper iswithdrawn through the reformed gap without making frictional contact, asa result the continuously driven roller need not entrain gears or otherrollers. Moreover, the feed and counterpressure roller equipped with theflat, and forming the releasable feed element, transports the sheet ofpaper through a substantial, but accurately defined, travel, at the endof which there is a pair of transport rollers of the transportmechanism. When, in this construction, the trailing edge ofa copyingsheet, which may be gripped by a pair of transport rollers of adownstream transport mechanism, leaves the withdrawing roller, the driveaffecting the latter becomes immediately effective for carrying the nextcopying sheet into the ready position.

In addition, upon reformation of the gap between the ready positionrollers, the counterpressure and feed roller is brought to a stop by alocking device.

The construction of the withdrawing means, particularly of thewithdrawing roller, has already been proposed and comprises a controlassuring that one sheet of copying paper follows another in tightsequence, so that the time lag between successive introductions oforiginals is substantially smaller. The present invention represents afurther improvement of this proposed arrangement.

The electrical control means comprises a relay circuit with a relay,adapted to be energized when a copying paper is in the ready positionand an original has been inserted. The relay controls the activation ofthe withdrawing and ready position rollers as will be more fullydescribed. The relay may be a delay type relay and may operate a warninglamp by means of a normally closed contact.

According to a further feature of the invention, the switching meanscomprises a relay circuit with a relay, adapted to be energized by theswitch in the operating position when a copying paper is in the readyposition, and which moves a contact bridging the rest contact of theswitch, in order to actuate the roller. The exact timing of the relaycircuit at the moment of actuation of the withdrawing roller is oflesser importance, because the withdrawing roller is defined and stoppedby the switch in the ready position. Conveniently, the relay may respondwith a delay. In a preferred embodiment, one relay may also operate awarning lamp, e.g., by means of a rest contact.

In another embodiment of the electrical control means, a charging anddischarging circuit for a capacitor is associated with the contactswitch actuated by the original. The discharge circuit includes aclutch-control magnet for actuating the withdrawing roller. The counterpressure and feed roller may be actuated by an impulse from thedischarge circuit by way of an operating magnet or may be actuatedthrough a mechanical linkage operably connected to the clutch-controlmagnet.

In the arrangement with capacitors, conveniently both the switch in theready position and the contact switch for the original have respectiveconnections with a capacitor and connect this connection to thedischarge circuit via the small clutch-control magnet which is adaptedto be energized alternatively by the contact switch, for switching onthe drive of the withdrawing roller, and by the switch for switchingthis drive off, while the release of the switches closes a chargingcircuit for the capacitors.

According to another feature of the invention, the circuit of the smallclutch-control magnet is connected to the winding of an actuating magnetfor the feed and counterpressure roller, causing the same to beenergized briefly, upon energization of the clutch-control magnet, forswitching on the drive of the withdrawing roller by the contact switch,but remains unenergized by the actuation of the switch. To this end, theenergizing circuit for the winding must incorporate a circuit breaker.

According to another preferred feature of the invention, connectingmeans are provided between the small clutch-control magnet and tworeversing switches, of which one, on actuation of the smallclutch-control magnet by the contact switch, causes a high-voltagetransformer for the charging device to be switched on and a warning lampindicating the ready state to be switched off, while the other isarranged in the energizing coil of an actuating magnet for the feed andcounterpressure roller and energizes this circuit on energization of theclutch-control magnet by the contact switch and opens it by the switchin the ready position. Conveniently, a lever on the small clutch-controlmagnet has arranged thereon an actuat ng lever for a switching bridgefor the reversing switches, which actuating lever is also connected to acounter which is advanced by half a step for every actuation of thesmall magnet. The magnet lever also control a clutch between theapparatus drive and the withdrawing roller.

According to yet another embodiment of the invention, the magnet leverof the clutch-control magnet is connected to a pivotable release lever,having a click-stop device cooperating with a pawl for the feed andcounterpressure roller. This device comprises a stop arrangement,preferably with a spring, between one arm of the release lever and thepawl (or pin), which releases the ratchet lock when the release leverhas been pivoted through a certain angle, in order to prepare thestopping of the counterpressure roller after one revolution. Preferably,the pawl is pivotable on the ratchet lever, and a spring is mountedbetween the pawl and a support and biases the pawl and the lever, afterthe release of the ratchet engagement, in the locking direction.

A further essential feature of the invention comprises a circult for adriving motor for the developing device, with a warning lamp indicatingthe ready state, and wherein the highvoltage transformer is connected bymeans of a contact breaker which opens when the apparatus, andparticularly the developing section, is opened.

The invention will be further described, by way of example, withreference to the accompanying drawings, illustrating the same in anonlimiting manner, and in which:

FIG. I is a schematic wiring diagram of a control arrange ment for thecopying apparatus according to the invention;

FIG. 2 is a schematic wiring diagram explanatory of another embodimentof the invention;

FIG. 3 shows diagrammatically a side elevation view of an apparatus,with the front cover dismantled and in partly broken awayrepresentation, and is explanatory of the arrangement of the elements ofFIG. 2 in the apparatus;

FIG. 4 is a side elevation view, in greater detail, of a unit omitted inFIG. 3;

FIG. 5 is a diagrammatical top view of the unit of FIG. 4 in partialcross section;

FIG. 6 is a partial view of the sheet dispenser drive, seen from the topand in partial cross section;

FIG. 7 shows another embodiment of the unit of FIG. 4; and

FIG. 8 is a top view of FIG. 7 in cross section along the lineVIII-VIII, with certain parts omitted.

For the sake of clarity, the arrangement of the individual parts willfirst be described with reference to FIG. 3. The copier shown therecomprises an exposure window or surface 1, above which is a guide 2 forthe original. Driven pairs of transport rollers 4, 5, 6, 7 are providedfor transporting the original, which is inserted through an opening 3.These rollers have a part of their circumference extending into theguide, and grip the original. Actuating arms 8, 9 and 10 of switches l1,l2 and 13, respectively, project into the guide and are operated by thepassage of the original therethrough.

The exposure window is illuminated by a light source 14. The light beam15, which is deflected by a mirror 16 and passes through an objectivelens 17, impinges on a transparent reproduction window 18, and thecopying sheet passes along this window. The light beam propagates alonga channel defined by the housing walls.

Above the channel is a stack holder 19 for copying sheets 20. Awithdrawing roller 21 runs on the top of the stack, and is mountedarticulately about the axis of a transport roller 22 which iscontinuously driven and arranged downstream in the direction of movementof the paper, as described further below. Roller 22 is so associatedwith a feed and counterpressure roller 23, with a flattened portion 24that the partof the periphery outside the flat24 can make drivingcontact with the transport roller 22, while, when the rollers 22, 23 arein the position of FIG. 3, a gap is formed between them. Behind the gap,there is a ready state switching bridge 25 with a passage, into whichprojects an arm 26 of a switch 27, which determines the readiness of thesheet of copying paper.

Following the switch 27, in the direction of movement of the copyingsheet, there is a charging device 28 and the curved guide elements 29. Acopying sheet passing through charging device 28 and along guideelements 29 is engaged by a pair of synchronously driven transportrollers 30 and 31, forming part of the transport mechanism of theapparatus, to transport the copying sheet in front of the reproductionwindow. As the copying sheet passes the reproduction window, it isengaged by a further driven pair of transport rollers 32 and 33. Betweenthe two pairs of rollers, the sheet of copying paper is held against thereproduction window by plate-shaped contact pressure means 34. Afterleaving the exposure station, which is constituted by the reproductionwindow [8, the copying sheet travels into the developing section 35 andthereafter through a drier and a heater, shown generally at 36.Downstream of the drier and heater, there is a delivery chute with adelivery slot 37.

The drive motor is indicated generally at 38 and drives a chain 39which, in turn, drives the transport element for moving the originalthrough the guide 2. Motor 38 also drives another chain 40 which drivesthe transport means for the sheet of copying paper.

FIG. I is a simplified circuit diagram, for explaining merely thecontrol for withdrawing the copying sheet from the stack and introducingit into the transport mechanism of the ap paratus, i.e., the first pairof rollers 30, 31. The withdrawing roller 21 is also shown. This figurealso includes the transport roller 22 and the counterpressure and feedroller 23 with the flat 24, and, behind the same, the switch 27 with theswitch arm 26. For the sake of clarity, the representation is somewhatexploded.

FIG. I also indicates diagrammatically that the drive, for example, themotor 38, is connected to the withdrawing roller 21 by a clutch 4!,adapted to be engaged by a linkage 42 via an operating magnet 43. Aspring arranged on the magnet effects the resetting and opening of theclutch 41 in the deenergized state.

This embodiment of the counterpressure and feed roller 23 has aswitching cam 45 fixedly mounted on its shaft 44. The cam has a step 46into which engages one end of a crank lever 54, mounted pivotably at 47,and the other end of which is hinged to an armature rod 49 of anactuating magnet 50. The switch rod may be surrounded by a return springSi, or this spring may be arranged within the magnet, as described inconjunction with magnet 43.

The cam is biased by a tension spring 52 mounted at 53 on the frame ofthe apparatus. When the lever 54 is withdrawn from the step 46 by theenergization of the magnet, the spring 52 pulls the feed roller intofrictional engagement with the transport roller 22, causing it to becarried along until the flat is again opposite the transport roller andthe lever 54 engages again into the step 46.

The switch 8 in FIG. 3 is shown at 55(8) in FIG. 1. It is actuated bythe original, and consists of a unit with two contacts of which, duringthe passage of the original, first one is closed and then the other isopened, in order to give a switching impulse.

The switch 27 is shown with its contacts at 56(27), in this case in thenoncopying position.

Supply conductors 58 and 59 are connected to a source of DC currentthrough a main switch 57. Conductor 59 is connected to the movable arm60 of switch 56, this arm being engageable with either of a pair offixed contacts 6] and 62. In the nonoperated state, arm 60 is engagedwith contact 6]. Actuating magnet 43 is connected between contact 61 andconductor 58. The switch assembly 55 and actuating member 50 areconnected in series between contact 62 and conductor 58.

In addition, a relay 63, which is preferably a delayed action relay, isconnected between contact 62 and a conductor 58. Relay 63 has normallyopen contacts 64 and 65 and normally closed contacts 66 and 67. Normallyopen contacts 65 are in the supply circuit of relay 63, and normallyopen contacts 64 are in parallel with the circuit including contact 61connecting conductor 59 to magnet 43.

Normally closed contacts 67 are interposed in a lead 68 connected, onthe one hand, between relay 63 and contacts 65 and, on the other hand,between magnet 50 and switch as sembly 55. Normally closed contacts 66are interposed in a lead connected between contact 62 and conductor 58,and including a lamp 69.

After the apparatus has been switched on, magnet 43 is energized throughengagement of contact arm 60 with contact 6!. Withdrawing roller 21transports a copying sheet which runs between rollers 22 and 23 toswitch arm 26, which disengages switch arm 60 from contact 6] andengages arm 60 with contact 62. This effects opening of clutch 41 andstops rotation of the withdrawing roller with the copying paper in theready position.

If an impulse is triggered off by an original via the switching unit 55,the magnet 50 will be energized. This lifts crank lever 54 to disengagestep 46 to release feed and counterpressure roller 23 which isaccelerated the spring 52. Roller 23 contact with the transport roller22 and advances the copying paper between these rollers, namely, in therepresentation of FIG. 3, through the charging device 28, until thepaper reaches the pair of rollers 30, 31. Then the flat of the feedroller 23 is again facing the transport roller 22, so that lever 54engages step 46 and the roller arrangement 22, 23 remains in the lockedposition. So long as the paper continues to advance, the switch arm 60makes contact with the contact 62.

The relay 63 has been energized by the switching impulse of theswitching unit 55 via the circuit 68. Either immediately or after abrief delay, contacts 64 and 65 close. Contacts 65 complete a holdingcircuit for relay 63, so that relay 63 remains energized until contactarm 26 returns into the illustrated position, after passage of thecopying sheet. The working roller contains a freewheeling device 71between the shaft 70 and the roller surface, permitting the freerotation of the roller under the action of the withdrawn sheet of paper.When the trailing edge of the sheet has left the roller 21 and hencealso the stack 20, the transporting action of the roller 2] becomeseffective, owing to the unidirectional action of the freewheelingdevice.

The rest contact 67 opens when relay 63 is deenergized in order toprevent a second energization of the magnet 50 during this operatingcycle. Preferably, the working contact 65 trails behind the rest contact67. The rest contact 66 extinguishes the lamp 69 after the insertion ofthe original, indicating that no original should be inserted.

When the trailing edge of the copying sheet of paper has left the switcharm 26, the contact arm 60 return into the position shown in thedrawing. The relay 63 is deenergized and its contacts also return intothe positions shown. The switch contact 61 takes over the furtherenergization of the magnet 43 so that the next copying sheet advancesinto the ready position, in which the switching arm 26 and the contactarm 6i are again reversed, causing the withdrawing roller to stop.

The lamp 69 lights up, giving the signal for the introduction of a neworiginal.

It may thus be seen that the switch 27 triggers a control action onlywhen actuated by the leading edge of the copying sheet, because theoriginal effects, by means of the switching unit, both the switching onof the feed and counterpressure roller 23 and the switching on of thewithdrawing roller 2!. Roller 21 remains in operation until a new sheetof copying paper actuates with its leading edge, the switching arm 26,which has meanwhile returned.

FIGS. 2 and 4 to 8 show two other solutions, based on the same controlprinciple. One solution comprises a more decentralized electricalcontrol, although cooperating with mechanical transmission members(FIGS. 2 and 4 to 6). The other solution is based mainly on mechanicallinkages. These figures and particularly those concerned with the secondsolution, show only differing parts. During the description of thissolution with reference to FIGS. 7 and 8, those parts which can beomitted in the circuit of FIG. 2 will be indicated.

In FIG. 2, the supply circuit is indicated at 72 as connected to a mainswitch 73. Upon closure of switch 73, various motors, such as fan motors74 and 75, a main motor 38, a further fan motor 79 and a heater 80 areenergized. Heater 80 is energized through thermal switches such as I63and I64 in such a manner that one thermal switch controls two heatingelements while the other thermal switch controls a further heatingelement, for the purpose of maintaining a predetermined temperature.

The circuit further comprises several light sources 14, controlled by aswitching contact 78. The operating winding of this contact is shown at77 and is connected in series with a temperature relay 76, with a unitcomprising two parallel switches 9 and I0. It has been shown in FIG. 3that the switch 9 is in the path of the original in front of the lightsource and the switch 10 behind the same. Thus, when the switch 9,closed, by the leading edge, is released by the passage of the trailingedge, the switch I0 has meanwhile been closed so that the excitation forthe actuating winding 77 is maintained for a sufficiently long period.Current is supplied to the switch circuit through a rectifier I03,associated with a capacitor I04. With an AC supply, these two parts alsomay provide a DC supply for the light source 14.

The drive motor 81 for the developer pump, and a primary winding of thehigh-voltage transformer 82, whose secondary is connected to thecharging device 28, are connected with a mains lead via a circuitbreaker 83 which is opened when a housing wall or flap (for example, 84in FIG. 3, affording access to the developing insert) is opened, so thatthe pump motor 81 and the transformer 82 are switched off. This is anadvantageous construction, particularly for changing or topping updeveloping substance, on the one hand, because the flap 84 gives accessto the developing insert 35 and returns automatically to the inoperativeposition, in which the liquid developer flows back into a storage tank,and, on the other hand, because the switching off of the high voltageprevents any danger for a person operating the apparatus.

The circuit controlled by the circuit breaker 83 contains also a warninglamp 85 indicating whether an original can be inserted after theapparatus has been switched on, i.e., whether a sheet of copying paperis in the ready position. Even if this is the case, the extinction ofthe lamp indicates, during the opening ofthe flap 84, that no copy canbe made.

It should be noted that parts shown in FIG. 3 are indicated in FIG. 2 bythe same reference numerals.

FIG. 2 shows, in addition to the On-Off switches 9 and 10, alreadymentioned, and operating the light source 14, also a reversing switch 8moved from the position shown into the other position by the advance ofthe original. The switch 27 is the switch controlling the ready positionof the copying sheet.

FIG. 2 shows further a small clutch-controlling magnet 88 and aswitching magnet 92. The small magnet operates with permanent magnet endpositions and switches a switching tongue, which is retained selectivelyand positively in one of two end positions. The mechanical connectionsof this tongue will be explained further below. It is sufficient tostate here that the small clutch-control magnet 88 operates the controlof a clutch for connecting the withdrawing roller 21 (FIG. 3), while theswitching magnet 92 effects the release of the feed and counterpressureroller 23 (FIG. 3), apart from other functions relating to the controlof the counter, whose step-by-step advance (two steps for every cycle ofone copy) reacts on reversing switches in the circuit. Such switches areindicated, by way of example, at 93 and 94.

In the following description, the functional cycle will be described,together with other circuit elements required for this purpose and whosearrangement follows from FIG. 2.

In principle, it should be mentioned that the circuit described operatesby means of switching impulses, which is of advantage from the viewpointof the accuracy of the control timing.

The switches are located in the position shown in the drawing. After theclosing of the main switch 73, the directly connected parts areoperated.

In this position, the clutch-control magnet 88, is in a position suchthat the clutch for the withdrawing roller 21 is engaged and copyingpaper is withdrawn from the stack. Let it be assumed that thiswithdrawing roller has a freewheeling device as described in conjunctionwith FIG. 1.

Before the copying paper has reached the ready position, the capacitor86 is charged via the switch 27. The charging is effected via a dampingresistor 95 and a rectifier 96 connected to the upper supply conductorby lead 91.

When the copying paper reverses the switch 27, the capacitor 86 isdischarged via the damping resistor 87 and the winding of clutch controlmagnet 88, which issues a switching impulse. This impulse uncouples theclutch for the withdrawing roller 21.

In addition, clutch-control magnet 88 also moves, by means to bedescribed later, a ratchet wheel of a first counting roller of a counter(FIGS. 4 and 5) through one-twentieth of a revolution. This causes theswitches 93 and 94 to be reversed by means of the mechanism shown inFIGS. 4 and 5.

The switch 93 causes the warning lamp 85 to light up, indicating that acopy can now be made. Through the switch 94 in its reversed position,the capacitor 97 is charged via the damping resistor 98 and a rectifier99, as well as a protecting resistor 100.

During the operations so far described, the high-voltage transformer hasbeen connected across the supply conductors by the switch 93. In theno-copy state, this takes place only during the first switching on ofthe apparatus. This HV transformer 82 is now switched off by themovement of the switch 93.

The apparatus is now prepared to make copies.

The inserted original operates the switches 8, 9, 10. The switching ofthe light sources by switches 8, 9, has already been explained.

Before the original reaches the switch 8, the capacitor l0! has beencharged via this reversing switch, the damping resistor 98, therectifier 99 and the lead 91. When the switch 8 is reversed by theoriginal, the capacitor 101 is discharged through the damping resistor102 and the coil of magnet 88. The latter is reversed to its originalposition, causing the clutch for the withdrawing roller 21 to reengage,and the roller to revolve. In addition, the ratchet wheel of the firstcounter is rotated through a further one twentieth ofa revolution sothat it has now advanced through one-tenth, i.e. by one unit.

Simultaneously the witches 93, 94 are actuated. Reversal of the switch93 to its illustrated position causes the lamp to go out and energizesthrough the HV transformer 82 the charging station 28. Reversing of theswitch 94 to its illustrated position discharges the capacitor 97through the wind ing 92 of the switching magnet, in order to release thefeed and counterpressure roller. The engagement between the feed anddrive rollers 22,23 causes the copying sheet to be transported out ofthe ready position, as described with reference to FIG. l. Thistransport continues until the sheet passes through the charging device28 and reaches the pair of transport rollers 30,31.

Since the switching magnet 92 for the feed and counterpressure roller 23has been excited for only for a short duration, the ratchet of thisroller 23 engages again after one revolution. Meanwhile, the originalswitches the light source 14 by means of the switches 9 and 10, asdescribed above.

When the trailing edge of the original leaves the switch 8, this switchreturns into its position shown in FIG. 2. In consequence, the capacitor101 is again charged through this switch, the damping resistor 98 andthe rectifier 99.

The switching magnet with the exciter coil 92, for the feed andcounterpressure roller 23, operates in the manner described parallel tothe clutch-controlling magnet 88. The magnet 92 can therefore be omittedand may be replaced by a special mechanical link on the working memberof magnet 88, for effecting the short duration release of the feed andcounterpressure roller 23, so that this roller is again stopped afterone revolution.

FIGS. 4, 5 and 6 show the construction of the switching magnet. In thesefigures, equivalent parts are designated by the same reference numeralsas in the other figures.

FIGS. 4 and 5 show the feed and counterpressure roller 23 with its shaft[05, mounted in a frame member 106. This shaft has on its end face or ona part mounted thereon a stop lug 106. A ratchet lever 107 is mounted onthe shaft and surrounds it after the manner of a clip and ishorizontally movable with its free end on the ratchet axle 108. Thetension spring 109 acts on the ratchet lever 107, corresponding to thespring 52in FIG. 1.

A switching drum paw] III] is mounted in the frame rotatably about thepawl axis 108. This pawl is connected to an armature rod 1] I of theoperating magnet 1 12, the winding of which is shown at 92 in FIG. 2.When the winding 92 is energized, the pawl Ill), engaging into a step113 on the feed and counterpressure roller 23, is lifted and the spring109 pulls this roller 23 into engagement with the transport roller 22.

The clutch-controlling magnet 88 (FIGS. 4 and 5) moves its switchingtongue 114 in the direction perpendicular to the plane of FIG. 4. Duringthis movement, the magnet lever 115 is carried along and engages thecoupling for the withdrawing roller 21, shown generally at 116, andconnecting the chain sprocket 117 (in a manner to be described in detailwith reference to FIG. 6). In addition, the magnet lever 115 entrains,by means of a pin 118 engaging into a slot 119, the switch lever 120.This lever 120 is mounted rotatably on the axis 121 of a counter 122.The counter 122 has a ratchet wheel 123, entrained by a clip 124 throughone-twentieth of one revolution, when the clip 124, mounted on themagnet lever 115, is moved. The ratchet wheel 123 is connected with thefirst number or digit disc of the counter 122 so that the twofoldactuation of the magnet lever, during the switching of theclutch-controlling magnet 88, causes the advance through one digit,while the switches 93 and 94 are simultaneously operated twice.

FIG. 6 shows the feed and counterpressure roller 23, and, above thesame, the transport roller 22 and the withdrawing roller 21. The shaft127 of the transport roller 22 carries two pivotable arms 125,126 whichsupport the shaft of the withdrawing roller 2]. Near its mounting 128 inthe frame 129, the shaft 127 carries a fixed gear 130, meshing with agear 131 which is fixedly connected with the sprocket 117. This sprocketis driven by the chain 40 (see FIG. 3).

The meshing gear 131 forms simultaneously the driving member of aclutch, formed, for example, by a spur toothing I32 (FIG. The drivenpart of this clutch, shown generally at 116, carries, on the outside,the gear ring 133 and, on the inside, a spur toothing I34, adapted to bebrought into engagement with the toothing 132. The driven part I16 withthe gear ring 133 is axially movable on a pin 136 mounted in a frameportion 135. The magnet lever 115 is connected to this driven part ofthe clutch such as by a part 137 engaged in a peripheral hub recess 138of gear 133. It may be seen from FIG. 5 that the reciprocating movementof the driven part engages and disengages the clutch, and thisengagement may be augmented by a spring, not shown in detail.

A bush 139 is mounted rotatably on the shaft 127 (FIG. 6) and isconnected firmly with a gear 140 which meshes with the gear I33. On theleft end of the bush, as viewed in FIG. 6, there is a driving gear I41,meshing via a transmission 142 with a drive pinion 143 on the shaft 144of the withdrawing roller 21. Preferably, in the hub of the pinion I43,i.e., between the gear ring and the shaft 144 of the withdrawing roller,there is a freewheeling device such that the withdrawing roller can berotated faster in its driving direction. The reduction gear 142 has aratio such that the withdrawing roller 21 revolves at a slightly smallerperipheral speed than the transport roller 21. Thus, when the copyingpaper is gripped by the transport roller 22 and the feed roller 23, itcan be pulled out from under the actuated withdrawing roller 21, asalready described.

In FIGS. 7 and 8, corresponding and equivalent parts are againdesignated by the same reference numerals as in FIGS. 4 and 5. It may beseen that this construction comprises only the switch 93, while theswitch 94 has been omitted. Also the actuating magnet I12 with itswinding 92, shown in FIG. 4, has been omitted.

The magnet lever 115 is again moved by the tongue 114 of theclutch-controlling magnet 88. The counter is carried along by the slot119, as already described. A release lever 147 is mounted rotatablyabout a pin 146 in the main frame plate 145 and engages, by means of apin I48, onto the actuating slot 149 of the magnet lever. The releaselever 147 is therefore rotated, by the movement of the magnet lever,about the mounting pin I46. The release lever 147 is a cranked lever andhas, on its other leg 150 an actuating lug 151, engaging into aratchetlike part 152 of a ratchet lever 153. Lever 153 is movable, onthe one hand, between a forked end I54 of the leg 150, and may be liftedoff the lug. The ratchet lever 153 has also mounted thereon a rod 155,passing through an over size hole in a fixed bearing plate 156, andconnected at its end, with clearance, to the arm 157 of the ratchet pawlIIO, pivotable about the ratchet axis 108, as already described. Theratchet lever 153 has also a pin 158, directed towards an arm 159 of therelease lever 147, but terminating at a distance therefrom in thestarting position.

Between the bearing plate 156 and the arm 157, there is a compressionspring 160.

When the release lever 147 is rotated. the lug I51 entrains the ratchetlever towards the right. It is here assumed that the magnet lever Imoves first in the direction of the arrow. By way of the entrainment ofthe ratchet lever I53 which is held by the spring 161 in engagement, theratchet lever 110 is withdrawn from the notch H3. The clearance preventstilting during the circular movement.

The unlocking releases the feed and counterpressure roller 23 as itcarries out one revolution.

During movement of release lever I47, arm 159 is rotatedcounterclockwise, as viewed in FIG. 8. After passing through the gapbetween it and pin I58, arm I59 engages pin 158 to operate this pin todisengage ratchet lever I53 from its locking engagement with lug 151.This enables the ratchet lever to be moved to the left by the spring 160so that the ratchet pawl I10 rests on the feed and counterpressureroller 23 and drops into the step after one rotation. Simultaneously,the ratchet lever I53 is withdrawn.

During switching off, when lever moves in the opposite direction, armI50 again engages its lug I51 behind the ratchetlike abutment.

This mechanical construction saves electrical circuitry and components.

We claim:

I. In copying apparatus of the type including an exposure device, guidemeans operable to guide an original past the exposure device, switchoperator means along the guide means actuated by an original, when theoriginal is within the zone of the exposure device, to operate a switchcontact arm, a stack holder for copying sheets, withdrawing meansassociated with the stack holder and operable to withdraw a top sheetfrom the latter, a reproduction device, copy sheet processing means,transport mechanism operable to transport copy sheets along a transportpath past the reproduction device and through the processing means, anintermittently operable copy sheet feed and contact pressure roller inthe transport path downstream of the stack holder, and a continuouslyoperable transport roller cooperable with the feed and contact pressureroller; the improvement comprising, in combination, copy sheet positiondetecting switch means in the path of the copy sheet immediatelydownstream of said feed and contact pressure roller and said transportroller cooperably therewith; drive means driving said transportmechanism and said transport roller in synchronism with each other;clutch means operable to connect said drive means to said withdrawingmeans for driving the latter in a copy sheet withdrawing direction; afreewheeling device included in said clutch means and providing for freemovement of said withdrawing means in the copy sheet withdrawingdirection; said position detecting switch means determining a readyposition of a copy sheet in said transport path; electrically energizedclutch operating means etfective, when energized, to engage said clutchmeans; a first energizing circuit for said clutch operating meansnormally closed by said position detecting switch means and opened, todisengage said clutch means, upon operation of said position detectingswitch means by a copy sheet in said ready position; means operable bysaid switch contact arm, responsive to actuation of said switch operatormeans by an original, to effect actuation of said feed and contactpressure roller from a rest position into a working position wherein itis driven in synchronism with said transport mechanism to feed a copysheet, in said ready position, into engagement with said transportmechanism; a second energizing circuit for said operating means closedby said switch contact arm, responsive to such actuation by said switchoperator means by an original, to reengage said clutch means to drivesaid withdrawing means; said feed and contact pressure roller having aconfiguration such that, in conjunction with said transport roller, itdefines, in its rest position, a gap to receive the leading edge of acopy sheet in said ready position, and such that, when in its workingposition, it grips a copy sheet between itself and said transport rollerto feed the copy sheet into engagement with said transport mechanism;said feed and contact pressure roller reattaining its rest position, tore-form said gap, immediately upon engagement of the copy sheet by saidtransport mechanism, to release the trailing edge of the copy sheet insaid gap; and transmission means, between said drive means and saidwithdrawing means, having a reduction ratio such that, upon engagementof said clutch means, said withdrawing means is driven at a copy sheetfeed rate less than that of said feed and contact pressure roller, withthe feed rate difference being compensated by said freewheeling device;whereby, simultaneously with actuation of said feed and contact pressureroller into its working position, said withdrawing means is driven totransport the next copying sheet to said ready position.

2. In copying apparatus, the improvement claimed in claim I, whereinsaid withdrawing means comprises rollers; said feed and contact pressureroller having a flattened portion which, when aligned with saidtransport roller, defines said gap and, when such alignment isinterrupted, said feed and contact pressure roller moves into drivingengagement with said transport roller; release means operativelyassociated with said feed and contact pressure roller to effect movementof said contact pressure roller from said rest position into saidworking position; an actuating magnet for said release means; andcircuit means connecting said actuating magnet with said switch contactarm and with said position detecting switch means.

3. ln copying apparatus, the improvement claimed in claim 1, includingswitching means operatively connected with said clutch operating means;a relay included in said switching means; a relay circuit including saidrelay, said contact switch means and said position detecting switchmeans; said relay circuit being closed by said switch contact arm whensaid position detecting switch means has been actuated by a copy sheetin said ready position; said first energizing circuit for saidclutch-operating means including a rest contact of said positiondetecting switch means; and a rest contact of said relay in parallelwith said rest contact of said position detecting switch means andincluded in said second energizing circuit.

4. In copying apparatus, the improvement claimed in claim 2, including acapacitor connected to said switch contact arm; a charging circuit and adischarging circuit for said capacitor controlled by said switch contactarm; and a clutch-controlling magnet in said discharge circuitcontrolling said clutch means; said capacitor providing a dischargepulse, of short duration, controlling said release means.

5. In copying apparatus, the improvement claimed in claim 3, including asignal lamp which, when energized, indicates readiness to copy with acopy sheet in said ready position; and an energizing circuit for saidsignal lamp including a rest contact of said relay.

6. in copying apparatus, the improvement claimed in claim 4, including asecond capacitor connected to said position detecting switch means; eachcapacitor being connected to said discharge circuit through saidclutch-controlling magnet; said clutch-controlling magnet being actuatedalternately by said switch contact arm, for engaging said clutch means,and by said position detecting switch means, for disengaging said clutchmeans; each of said contact and position detecting switch means, in itsrest position, closing a charging circuit for its respective capacitor.

7. In copying apparatus, the improvement claimed in claim 4, in whichthe winding of said actuating magnet is connected to saidclutch-controlling magnet and is energized, together with saidclutch-controlling magnet, for a brief period, for engaging said clutchmeans, by operation of said switch contact arm, and is deenergized byoperation of said position detecting switch means.

8. In copying apparatus, the improvement claimed in claim 7, in whichsaid actuating magnet is provided with a pawl operable on said releasemeans; said release means including a spring biased cam and cam followerarrangement; said cam follower being actuated by said pawl.

9. In copying apparatus, the improvement claimed in claim 4, including amagnet lever operable by energization of said clutch-controlling magnet:a detent member and a ratchet lever operable to control said releasemeans; a pivotable release lever interconnecting said magnet lever andsaid detent member; said release lever having a first arm; a connection,including a spring, provided, with clearance, between said first arm andsaid ratchet lever and operable to effect release of said detent memberresponsive to a predetermined rotation of said release lever in order toprepare for stopping of said feed and contact pressure roller after onerevolution of the latter; a pawl pivoted on said ratchet lever; and aspring connected between this pawl and a fixed point and biasing saidpawl and said ratchet lever, after release of the click-stop engagement,to reestablish such engagement.

10. in copying apparatus, the improvement claimed in claim 6, includinga lever operable by said clutch-controlling magnet; a switching bridgeoperable to operate said reversing switches; a pivotable actuating leverarticulatedly interconnecting said switching bridge and said magnetlever; and a counter having an actuating lever connected to said magnetlever and advanced, by half a unit step, responsive to each sotuation ofsaid clutch-controlling magnet.

l l. In copying apparatus, the improvement claimed in claim 6, whereinsaid copying apparatus includes a developing device comprising part ofsaid processing means and a housing including an openable flap adjacentsaid developing device: said drive means including a drive motor; anenergizing circuit for said drive motor, said developing device, saidwarning lamp and said high-voltage transformer; and a circuit breaker insaid energizing circuit retained closed when said housing is closed andopening when said flap is opened.

12. in copying apparatus, the improvement claimed in claim 6, in whichsaid copying apparatus includes a charging device for the copy sheets; ahigh-voltage transformer connected to said charging device to energizethe latter; a pair of reversing switches; a warning lamp indicating thereadiness to produce a copy; a first circuit including said lamp andsaid actuating magnet, and controlled by one reversing switch; said onereversing switch, responsive to energization of said clutchcontrollingmagnet, connecting said transformer to a source of potential anddeenergizing said warning lamp and, responsive to deenergization of saidclutch-controlling magnet disconnecting said transformer from saidsource of potential and energizing said warning lamp; the otherreversing switch being included in a second circuit including theexciting winding of said actuating magnet, and closing said secondcircuit responsive to energization of said clutch-controlling magnet bysaid switch contact arm, and opening said second circuit responsive todeenergization of said clutch-controlling magnet by said positiondetecting switch means.

13. In copying apparatus, the improvement claimed in claim 10, in whichsaid magnet lever is connected with said clutch means to operate thelatter; and reduction wearing between said clutch means and saidwithdrawing rouer and including said freewheeling device.

1. In copying apparatus of the type including an exposure device, guidemeans operable to guide an original past the exposure device, switchoperator means along the guide means actuated by an original, when theoriginal is within the zone of the exposure device, to operate a switchcontact arm, a stack holder for copying sheets, withdrawing meansassociated with the stack holder and operable to withdraw a top sheetfrom the latter, a reproduction device, copy sheet processing means,transpoRt mechanism operable to transport copy sheets along a transportpath past the reproduction device and through the processing means, anintermittently operable copy sheet feed and contact pressure roller inthe transport path downstream of the stack holder, and a continuouslyoperable transport roller cooperable with the feed and contact pressureroller; the improvement comprising, in combination, copy sheet positiondetecting switch means in the path of the copy sheet immediatelydownstream of said feed and contact pressure roller and said transportroller cooperably therewith; drive means driving said transportmechanism and said transport roller in synchronism with each other;clutch means operable to connect said drive means to said withdrawingmeans for driving the latter in a copy sheet withdrawing direction; afreewheeling device included in said clutch means and providing for freemovement of said withdrawing means in the copy sheet withdrawingdirection; said position detecting switch means determining a readyposition of a copy sheet in said transport path; electrically energizedclutch operating means effective, when energized, to engage said clutchmeans; a first energizing circuit for said clutch operating meansnormally closed by said position detecting switch means and opened, todisengage said clutch means, upon operation of said position detectingswitch means by a copy sheet in said ready position; means operable bysaid switch contact arm, responsive to actuation of said switch operatormeans by an original, to effect actuation of said feed and contactpressure roller from a rest position into a working position wherein itis driven in synchronism with said transport mechanism to feed a copysheet, in said ready position, into engagement with said transportmechanism; a second energizing circuit for said operating means closedby said switch contact arm, responsive to such actuation by said switchoperator means by an original, to reengage said clutch means to drivesaid withdrawing means; said feed and contact pressure roller having aconfiguration such that, in conjunction with said transport roller, itdefines, in its rest position, a gap to receive the leading edge of acopy sheet in said ready position, and such that, when in its workingposition, it grips a copy sheet between itself and said transport rollerto feed the copy sheet into engagement with said transport mechanism;said feed and contact pressure roller reattaining its rest position, tore-form said gap, immediately upon engagement of the copy sheet by saidtransport mechanism, to release the trailing edge of the copy sheet insaid gap; and transmission means, between said drive means and saidwithdrawing means, having a reduction ratio such that, upon engagementof said clutch means, said withdrawing means is driven at a copy sheetfeed rate less than that of said feed and contact pressure roller, withthe feed rate difference being compensated by said freewheeling device;whereby, simultaneously with actuation of said feed and contact pressureroller into its working position, said withdrawing means is driven totransport the next copying sheet to said ready position.
 2. In copyingapparatus, the improvement claimed in claim 1, wherein said withdrawingmeans comprises rollers; said feed and contact pressure roller having aflattened portion which, when aligned with said transport roller,defines said gap and, when such alignment is interrupted, said feed andcontact pressure roller moves into driving engagement with saidtransport roller; release means operatively associated with said feedand contact pressure roller to effect movement of said contact pressureroller from said rest position into said working position; an actuatingmagnet for said release means; and circuit means connecting saidactuating magnet with said switch contact arm and with said positiondetecting switch means.
 3. In copying apparatus, the improvement claimedin claim 1, including switching means opeRatively connected with saidclutch operating means; a relay included in said switching means; arelay circuit including said relay, said contact switch means and saidposition detecting switch means; said relay circuit being closed by saidswitch contact arm when said position detecting switch means has beenactuated by a copy sheet in said ready position; said first energizingcircuit for said clutch-operating means including a rest contact of saidposition detecting switch means; and a rest contact of said relay inparallel with said rest contact of said position detecting switch meansand included in said second energizing circuit.
 4. In copying apparatus,the improvement claimed in claim 2, including a capacitor connected tosaid switch contact arm; a charging circuit and a discharging circuitfor said capacitor controlled by said switch contact arm; and aclutch-controlling magnet in said discharge circuit controlling saidclutch means; said capacitor providing a discharge pulse, of shortduration, controlling said release means.
 5. In copying apparatus, theimprovement claimed in claim 3, including a signal lamp which, whenenergized, indicates readiness to copy with a copy sheet in said readyposition; and an energizing circuit for said signal lamp including arest contact of said relay.
 6. In copying apparatus, the improvementclaimed in claim 4, including a second capacitor connected to saidposition detecting switch means; each capacitor being connected to saiddischarge circuit through said clutch-controlling magnet; saidclutch-controlling magnet being actuated alternately by said switchcontact arm, for engaging said clutch means, and by said positiondetecting switch means, for disengaging said clutch means; each of saidcontact and position detecting switch means, in its rest position,closing a charging circuit for its respective capacitor.
 7. In copyingapparatus, the improvement claimed in claim 4, in which the winding ofsaid actuating magnet is connected to said clutch-controlling magnet andis energized, together with said clutch-controlling magnet, for a briefperiod, for engaging said clutch means, by operation of said switchcontact arm, and is deenergized by operation of said position detectingswitch means.
 8. In copying apparatus, the improvement claimed in claim7, in which said actuating magnet is provided with a pawl operable onsaid release means; said release means including a spring biased cam andcam follower arrangement; said cam follower being actuated by said pawl.9. In copying apparatus, the improvement claimed in claim 4, including amagnet lever operable by energization of said clutch-controlling magnet:a detent member and a ratchet lever operable to control said releasemeans; a pivotable release lever interconnecting said magnet lever andsaid detent member; said release lever having a first arm; a connection,including a spring, provided, with clearance, between said first arm andsaid ratchet lever and operable to effect release of said detent memberresponsive to a predetermined rotation of said release lever in order toprepare for stopping of said feed and contact pressure roller after onerevolution of the latter; a pawl pivoted on said ratchet lever; and aspring connected between this pawl and a fixed point and biasing saidpawl and said ratchet lever, after release of the click-stop engagement,to reestablish such engagement.
 10. In copying apparatus, theimprovement claimed in claim 6, including a lever operable by saidclutch-controlling magnet; a switching bridge operable to operate saidreversing switches; a pivotable actuating lever articulatedlyinterconnecting said switching bridge and said magnet lever; and acounter having an actuating lever connected to said magnet lever andadvanced, by half a unit step, responsive to each actuation of saidclutch-controlling magnet.
 11. In copying apparatus, the improvementclaimed in claim 6, wherein said copying apparatus includes a developingdevice Comprising part of said processing means and a housing includingan openable flap adjacent said developing device: said drive meansincluding a drive motor; an energizing circuit for said drive motor,said developing device, said warning lamp and said high-voltagetransformer; and a circuit breaker in said energizing circuit retainedclosed when said housing is closed and opening when said flap is opened.12. In copying apparatus, the improvement claimed in claim 6, in whichsaid copying apparatus includes a charging device for the copy sheets; ahigh-voltage transformer connected to said charging device to energizethe latter; a pair of reversing switches; a warning lamp indicating thereadiness to produce a copy; a first circuit including said lamp andsaid actuating magnet, and controlled by one reversing switch; said onereversing switch, responsive to energization of said clutch-controllingmagnet, connecting said transformer to a source of potential anddeenergizing said warning lamp and, responsive to deenergization of saidclutch-controlling magnet disconnecting said transformer from saidsource of potential and energizing said warning lamp; the otherreversing switch being included in a second circuit including theexciting winding of said actuating magnet, and closing said secondcircuit responsive to energization of said clutch-controlling magnet bysaid switch contact arm, and opening said second circuit responsive todeenergization of said clutch-controlling magnet by said positiondetecting switch means.
 13. In copying apparatus, the improvementclaimed in claim 10, in which said magnet lever is connected with saidclutch means to operate the latter; and reduction gearing between saidclutch means and said withdrawing roller and including said freewheelingdevice.